|Publication number||US4309993 A|
|Application number||US 06/127,554|
|Publication date||Jan 12, 1982|
|Filing date||Mar 6, 1980|
|Priority date||Mar 6, 1980|
|Publication number||06127554, 127554, US 4309993 A, US 4309993A, US-A-4309993, US4309993 A, US4309993A|
|Inventors||Richard I. Brown|
|Original Assignee||Baxter Travenol Laboratories, Inc.|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (14), Referenced by (47), Classifications (12)|
|External Links: USPTO, USPTO Assignment, Espacenet|
This invention concerns a novel liquid flow sensing apparatus and, more particularly, a sensing apparatus that is extremely sensitive to cessation of liquid flow and is adapted to be precisely calibrated.
Although the illustrative embodiment of the present invention concerns an occluded vein sensor for use in a membrane plasmapheresis system, it is to be understood that no limitation with respect to usage of the liquid flow sensing apparatus is intended except as set forth in the appended claims.
Plasmapheresis involves the separation of plasma from whole blood, the collection of the plasma and the return of the red cells to the donor. It is desirable, if not essential, that the blood flow be carefully monitored so that an occluded vein is detected. If a vein becomes occluded, it is essential that the withdrawal of blood be terminated immediately.
Precise detecting of the blood flow is therefore necessary, and it is important that the occluded vein sensing device have the ability to be calibrated precisely. It is, therefore, an object of the invention to provide a liquid flow sensing apparatus that is very sensitive to changes in liquid flow.
Another object of the present invention is to provide a liquid flow sensing apparatus that can be calibrated very accurately.
A further object of the present invention is to provide a liquid flow sensing apparatus that can be used as an occluded vein sensor.
A still further object of the present invention is to provide a liquid flow sensing apparatus that is simple in construction and efficient to manufacture.
Other objects and advantages of the present invention will become apparent as the description proceeds.
In accordance with the present invention, a liquid flow sensing apparatus is provided which comprises a base member and an eddy current proximity sensor carried by the base member. A housing is connected to the base member for receiving a flexible pressure pillow which expands and contracts in response to liquid flow and cessation of liquid flow, respectively.
A metallic spring member is carried by the base member for contact with the flexible pressure pillow. The spring member is movable relative to the eddy current proximity sensor in response to expansion and contraction of the pressure pillow.
The housing includes a platen that is pivotally connected to the base member. Calibration means are provided for initially adjusting the position of the platen to apply a force against the pressure pillow and thereby move the spring member relative to the eddy current proximity sensor.
In the illustrative embodiment, the base member includes a pair of opposed side members and a pivot pin is carried by the side members. The platen includes a pair of side plates that are coupled to the pivot pin.
In the illustrative embodiment, the calibration means includes a spring biased screw coupling the platen to the housing.
In the illustrative embodiment, the liquid flow sensing apparatus is an occluded vein sensor and the flexible pressure pillow comprises a generally pillow-shaped plastic device having a blood flow inlet and a blood flow outlet, and an additional saline inlet is connected to the plastic device and extends generally perpendicular to the blood flow inlet.
In accordance with the present invention, a method is provided for sensing an occluded vein. The method comprises the steps of connecting flexible tubing to a vein and providing a flexible pressure pillow along the tubing. The pillow is inserted into a housing and in contact with a metallic member. The sensing is calibrated by adjusting the housing to move the pillow and the metallic member relative to an eddy current proximity sensor. Thereafter, further movement of the metallic member away from the eddy current proximity sensor is detected.
A more detailed explanation of the invention is provided in the following description and claims, and is illustrated in the accompanying drawings.
FIG. 1 is a side elevational view of a liquid flow sensing apparatus constructed in accordance with the principles of the present invention;
FIG. 2 is a top plan view thereof, taken along the plane of the line 2--2 of FIG. 1;
FIG. 3 is a cross-sectional elevation taken along the plane of the line 3--3 of FIG. 2;
FIG. 4 is a front view of a liquid flow sensing apparatus constructed in accordance with the present invention;
FIG. 5 is one form of a schematic diagram for wiring the proximity sensor;
FIG. 6 is another form of a schematic diagram for wiring the proximity sensor; and
FIG. 7 is a graph used for calibrating the liquid flow sensing apparatus of the present invention.
The liquid flow sensing apparatus of the present invention will be referred to as an occluded vein sensor in this detailed description. The occluded vein sensor may be mounted on a plasmapheresis apparatus 10 (FIG. 1). The occluded vein sensor comprises a base member 12 having a generally triangular cross-sectional configuration (FIG. 3) and having a bottom 14, a front portion 16, a top portion 18 and a pair of opposed side members 19, 20. Side members 19, 20 carry a pivot pin 22 to which is connected side plates 23, 24 of a housing 26.
Housing 26 comprises a platen portion 28 which defines a slot 30 and an opening 32 through which an adjustment screw 34 extends. Side plates 23, 24 are integrally formed with platen 28 and extend downwardly from platen 28. It can be seen that housing 26 is pivotable with respect to base member 12, about pivot pin 22.
Although platen 28 is illustrated as being generally planar in the illustrative embodiment, it is to be understood that platen 28 could be curvilinear, if desired.
An eddy current proximity sensor 36, which will be described in more detail below, is carried by base member 12, as illustrated in FIGS. 3 and 4 in particular. A non-metallic spacer 38 is attached to the top surface of top portion 18 of base member 12 and a leaf spring 40 is connected to base member 12 by means of a front panel 42 fastening a fixed portion 44 of leaf spring 40 to the front panel 16 of base member 12. The portion of leaf spring 40 which overlies spacer 38 and eddy current proximity sensor 36 is movable with respect to the eddy current proximity sensor, as seen most clearly in FIG. 3.
Housing 26 is adapted to receive a pressure pillow 50 which is preferably formed of a vinyl plastic material having a generally pillow shape, with a blood inlet 52, a blood outlet 54, and a saline inlet 56 which is connected to the pillow 54 and extends generally perpendicular to the blood inlet 52 and blood outlet 54. Flexible tubing 58 is coupled to inlet 52 and outlet 54 and in series with the patient's vein, while a saline solution is coupled to saline inlet 56 via another flexible tube (not shown). In the illustrative embodiment, pressure pillow 50 is formed by turning a sheet of vinyl plastic material and forming a pair of two-way seals 60, 62. The pressure pillow 50 is insertable into the housing as illustrated, with saline inlet 56 sliding into slot 30.
As illustrated most clearly in FIG. 3, screw 34 includes a thumbwheel 64 for aid in turning the screw and is biased generally upwardly by means of a spring 66. Clockwise rotation of the screw will cause platen 28 to pivot in the counterclockwise direction about pivot 22 (with respect to FIG. 3), thereby essentially bringing the platen closer to top portion 18 of base member 12. The pressure pillow 56 is inserted into the opening defined by the housing in the illustrated manner, with the bottom of pressure pillow 50 resting upon leaf spring 40. Leaf spring 40 is formed of a metallic material. The metallic material may comprise solid steel or the metallic material may comprise an insulative substance coated with or containing metallic foil. As thumbwheel 64 is rotated in the clockwise direction, platen 28 will move the pressure pillow downward to force leaf spring 40 toward proximity sensor 36. In order to calibrate the system, thumbwheel 34 is turned to a no-alarm position. If a vein is occluded or if liquid flow ceases for any reason, the contraction of the pressure pillow 50 will cause the leaf spring 40 to move away from proximity sensor 36, thereby causing an alarm condition.
As a specific example, although no limitation is intended, proximity sensor 36 may be a ferrous metal sensitive XK proximity sensor manufactured by Microswitch of Freeport, Illinois (a division of Honeywell), Model PK8759 0. Microswitch Series XK proximity sensors are ferrous metal sensitive and detect stationary or moving targets. They are actuated without physical contact or attraction between the sensor and the target. Ferrous metal of any thickness or non-ferrous metal foil targets will operate the sensor. The sensor utilizes the eddy current principle. An electromagnetic field is generated by a coil in the face of the sensor. When the field is absorbed by the target, eddy currents are generated in it. These eddy currents present a reflected load to the oscillator, reducing its signal level. This change in level is amplified by the integrator circuitry which drives a Schmitt trigger coupled to an output transistor, switching the load to provide a digital output.
A pair of schematic wiring diagrams for wiring the proximity sensor 36 is illustrated in FIGS. 5 and 6. The "load" may constitute an alarm and/or the liquid pump circuit, whereby movement of the leaf spring away from the proximity sensor causes actuation of the alarm and deactuation of the liquid pump.
In FIG. 7, a graph is illustrated for aiding the physician in calibrating the occluded vein sensor. First, thumbscrew 64 is turned clockwise to push the pressure pillow 50 against leaf spring 40, moving the leaf spring 40 closer to the proximity sensor 36, until there is no alarm and/or the liquid pump is operating. Second, if the physician does not want the alarm to be actuated and/or the pump to stop pumping until the line pressure is 200 millimeters of mercury, a horizontal line is extended from the 200 millimeter mark on the vertical axis of FIG. 7 to the shaded portion, which would indicate that the adjustment screw 64 should be turned clockwise further between one-half and three-quarter turns.
It can be seen that a liquid flow sensing apparatus has been provided which enables precise calibration and utilizes an eddy current proximity sensor for providing sensitive detection. Spacer 38 aids in providing the proper spacing for the proximity sensor and also in sealing an occluded vein sensor from blood spills.
Although an illustrative embodiment of the invention has been shown and described, it is to be understood that various modifications and substitutions may be made without departing from the novel spirit and scope of the present invention.
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2847562 *||Jun 22, 1953||Aug 12, 1958||Streeter Amet Co||Car actuated circuit controller|
|US2885506 *||Apr 28, 1955||May 5, 1959||Western Electric Co||Fluid pressure sensitive control devices|
|US3167691 *||Mar 23, 1960||Jan 26, 1965||Electrical apparatus|
|US3413095 *||Jun 14, 1965||Nov 26, 1968||Mogens L. Bramson||Membrane oxygenator|
|US3423551 *||Jan 12, 1966||Jan 21, 1969||Beertronic Corp||Pressure sensitive switch|
|US3424883 *||Nov 15, 1965||Jan 28, 1969||Don E Heskett||Fluid conducting device and pressure sensitive control means|
|US3827828 *||Dec 26, 1972||Aug 6, 1974||Edwards M||Fluid pump control system|
|US3833013 *||Apr 6, 1972||Sep 3, 1974||Baxter Laboratories Inc||Self-valving fluid reservoir and bubble trap|
|US3841157 *||May 31, 1973||Oct 15, 1974||Willock C||Drop bulb pressure-measuring device|
|US3907504 *||Apr 6, 1973||Sep 23, 1975||Gen Electric||Blood oxygenation system including automatic means for stabilizing the flow rate of blood therethrough|
|US3949734 *||Jul 22, 1974||Apr 13, 1976||Miles Lowell Edwards||Fluid pump control system|
|US4135124 *||Jun 20, 1977||Jan 16, 1979||Robert Buck||Electronic monitoring system with selective signal inverter|
|US4137915 *||Jun 3, 1977||Feb 6, 1979||Dean Kamen||Flow control for an intravenous feeding system|
|US4227171 *||Dec 21, 1978||Oct 7, 1980||Denki Onkyo Co., Ltd.||Liquid level sensing means|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US4369780 *||Aug 21, 1980||Jan 25, 1983||Sharp Kabushiki Kaisha||Blocking condition detection device in a medical fluid injection system|
|US4501583 *||Jun 15, 1983||Feb 26, 1985||Extracorporeal, Inc.||Hemodialysis access monitors|
|US4534756 *||Apr 11, 1983||Aug 13, 1985||Ivac Corporation||Fault detection apparatus and method for parenteral infusion system|
|US4778445 *||Nov 28, 1986||Oct 18, 1988||Minnesota Mining And Manufacturing Company||Centrifugal blood pump with backflow detection|
|US5171212 *||Feb 8, 1991||Dec 15, 1992||Minnesota Mining And Manufacturing Company||Blood pumping system with backflow warning|
|US5335551 *||Nov 12, 1992||Aug 9, 1994||Kanegafuchi Kagaku Kogyo Kabushiki Kaisha||Pillow type pressure detector|
|US5368554 *||Nov 20, 1992||Nov 29, 1994||Minnesota Mining And Manufacturing Company||Blood pumping system with selective backflow warning|
|US5564420 *||Apr 14, 1995||Oct 15, 1996||Minnesota Mining And Manufacturing Company||Medical device with EMI detection and cancellation|
|US5695473 *||Jul 27, 1994||Dec 9, 1997||Sims Deltec, Inc.||Occlusion detection system for an infusion pump|
|US5935099 *||Jan 10, 1997||Aug 10, 1999||Sims Deltec, Inc.||Drug pump systems and methods|
|US5935106 *||Nov 26, 1997||Aug 10, 1999||Sims Deltec, Inc.||Occlusion detection system for an infusion pump|
|US6077055 *||Dec 3, 1998||Jun 20, 2000||Sims Deltec, Inc.||Pump system including cassette sensor and occlusion sensor|
|US7186230||Feb 27, 2003||Mar 6, 2007||Therakos, Inc||Method and apparatus for the continuous separation of biological fluids into components|
|US7211037||Sep 3, 2003||May 1, 2007||Therakos, Inc.||Apparatus for the continuous separation of biological fluids into components and method of using same|
|US7347836||Feb 5, 2002||Mar 25, 2008||Smiths Medical, Inc.||Drug pump systems and methods|
|US7479123||Sep 3, 2003||Jan 20, 2009||Therakos, Inc.||Method for collecting a desired blood component and performing a photopheresis treatment|
|US7503889||Apr 19, 2006||Mar 17, 2009||Dennis Briggs||Apparatus for the continuous separation of biological fluids into components and method of using same|
|US7654976||Oct 31, 2007||Feb 2, 2010||Smiths Medical Asd, Inc.||Drug pump systems and methods|
|US7850634||Dec 19, 2006||Dec 14, 2010||Therakos, Inc.||Method for collecting a desired blood component and performing a photopheresis treatment|
|US7914477||Apr 19, 2006||Mar 29, 2011||Therakos, Inc.||Apparatus for the continuous separation of biological fluids into components and method of using same|
|US8133197||May 2, 2008||Mar 13, 2012||Smiths Medical Asd, Inc.||Display for pump|
|US8149131||Aug 3, 2006||Apr 3, 2012||Smiths Medical Asd, Inc.||Interface for medical infusion pump|
|US8250483||Feb 28, 2002||Aug 21, 2012||Smiths Medical Asd, Inc.||Programmable medical infusion pump displaying a banner|
|US8435206||Feb 5, 2007||May 7, 2013||Smiths Medical Asd, Inc.||Interface for medical infusion pump|
|US8504179||Feb 28, 2002||Aug 6, 2013||Smiths Medical Asd, Inc.||Programmable medical infusion pump|
|US8858526||Aug 3, 2006||Oct 14, 2014||Smiths Medical Asd, Inc.||Interface for medical infusion pump|
|US8952794||Mar 13, 2012||Feb 10, 2015||Smiths Medical Asd, Inc.||Interface for medical infusion pump|
|US8954336||Feb 22, 2005||Feb 10, 2015||Smiths Medical Asd, Inc.||Server for medical device|
|US8965707||Aug 3, 2006||Feb 24, 2015||Smiths Medical Asd, Inc.||Interface for medical infusion pump|
|US9238097||Jun 7, 2010||Jan 19, 2016||Therakos, Inc.||Method for collecting a desired blood component and performing a photopheresis treatment|
|US20020183693 *||Feb 5, 2002||Dec 5, 2002||Sims Deltec, Inc.||Drug pump systems and methods|
|US20030163088 *||Feb 28, 2002||Aug 28, 2003||Blomquist Michael L.||Programmable medical infusion pump|
|US20030163789 *||Feb 28, 2002||Aug 28, 2003||Blomquist Michael L.||Programmable medical infusion pump displaying a banner|
|US20030181305 *||Feb 27, 2003||Sep 25, 2003||Briggs Dennis A.||Method and apparatus for the continuous separation of biological fluids into components|
|US20040124157 *||Sep 3, 2003||Jul 1, 2004||Dennis Briggs|
|US20040127840 *||Sep 3, 2003||Jul 1, 2004||Steve Gara||Blood separation apparatus and method of using the same|
|US20040127841 *||Sep 3, 2003||Jul 1, 2004||Dennis Briggs||Method for collecting a desired blood component and performing a photopheresis treatment|
|US20050246416 *||Feb 22, 2005||Nov 3, 2005||Blomquist Michael L||Server for medical device|
|US20060186061 *||Apr 19, 2006||Aug 24, 2006||Dennis Briggs|
|US20060189469 *||Apr 19, 2006||Aug 24, 2006||Dennis Briggs|
|US20080033361 *||Feb 5, 2007||Feb 7, 2008||Smiths Medical Md, Inc.||Interface for medical infusion pump|
|US20080033749 *||Aug 3, 2006||Feb 7, 2008||Blomquist Michael L||Interface for medical infusion pump|
|US20080034323 *||Aug 3, 2006||Feb 7, 2008||Blomquist Michael L||Interface for medical infusion pump|
|US20080126969 *||Aug 3, 2006||May 29, 2008||Blomquist Michael L||Interface for medical infusion pump|
|US20100298752 *||Jun 7, 2010||Nov 25, 2010||Dennis Briggs||Method for collecting a desired blood component and performing a photopheresis treatment|
|EP0208061A1 *||Mar 27, 1986||Jan 14, 1987||Biotest Pharma GmbH||Method and device for obtaining blood plasma|
|EP0597145A1 *||Nov 12, 1992||May 18, 1994||Kanegafuchi Kagaku Kogyo Kabushiki Kaisha||Pillow type pressure detector|
|U.S. Classification||604/28, 200/81.00R, 417/45, 338/32.00R, 604/503, 604/31, 361/180, 200/81.90R, 73/728|